A compression stocking with the ability to change the applied pressure contains a foot portion, a calf portion, and a slit. The slit functions as a size-adjustable opening so that the compression stocking can be worn and removed conveniently. The size of the slit is controlled by at least one cord which is tethered around a first set of pulleys and a second set of pulleys. When the pressure applied by the foot portion and the calf portion needs to varied, a user adjusts the cord around the first set of pulleys and the second set of pulleys so that the overall pressure is changed. By utilizing a pressure sensing device, the exact pressure can be measured. Moreover, by using a cord retention device the probability of the cord loosening around the leg can be eliminated.